Shoe Conditions Research Articles

A Study Protocol to Investigate the Influence of Shoe Collar Height on Coordination and Plantar Pressure Distribution during Locomotion in Young Adults

Introduction: Higher collar heights are often associated with increased ankle support and stability while lower collar heights may allow for greater ankle flexibility. The design of footwear, particularly the height of the collar, plays a crucial role in influencing how individuals move and distribute pressure on their feet during various activities. Aim: To investigate how high-cut, low-cut and mid-cut shoes affects coordination and plantar pressure distribution during walking in young adults. Materials and Methods: Ninety-five healthy college-going students aged between 18-25 years wearing casual shoes for atleast six hours a day for 5 days a week for more than 6 months will be recruited through convenience sampling method. Participants shall be grouped based on the design and cut height of their shoes into high-cut, low-cut and mid-cut categories. Coordination tests under barefoot and shod conditions will be used to assess coordination. Plantar pressure in barefoot condition for different foot regions will be determined through Harris mat and Podia Scan® software. Results: Kolmogorov-Smirnov test will be used to determine normality (n>50). Parametric (Paired t-test) or non-parametric test (Wilcoxon-Signed Rank Test) will be used for within-group analysis. For between-group analysis, parametric (One-way ANOVA) or nonparametric test (Kruskal-Wallis H test) will be used. Conclusion: Understanding the relationship between shoe collar height and lower extremity coordination as well as foot pressure distribution is crucial for designing footwear that optimises performance, minimises injury risk, and enhances overall movement efficiency across various physical activities

Influence of Footwear Selection on Youth Running Biomechanics: A Pilot Study.

The relationship of running biomechanics, footwear, and injury has been studied extensively in adults. There has been little research on the effects of footwear on running biomechanics in youth. Running biomechanics of youth will be significantly affected by changes in footwear. Minimal shoe running will demonstrate similarities to barefoot. Crossover study design: randomized trial. Level 2. A total of 14 active male youth (8-12 years old) participants with no previous exposure to minimalist shoes or barefoot running had running biomechanics (lower extremity sagittal plane kinematics and vertical ground reaction forces [vGRFs]) collected and analyzed in 3 footwear conditions (barefoot, traditional, and minimal shoe). The average vertical loading rate (AVLR) was significantly greater running barefoot (173.86 bodyweights per second [BW/s]) and in the minimal shoe (138.71 BW/s) compared with the traditional shoe (78.06 BW/s), (P < 0.01). There were significant differences between shoe conditions for knee flexion at initial contact (P < 0.01), knee sagittal plane excursion (P < 0.01), peak dorsiflexion (P < 0.01), and dorsiflexion at initial contact (P = 0.03). No participants displayed a forefoot-strike during this study. The introduction of barefoot and minimalist running in habitually shod youth significantly affected the running biomechanics of youth and caused immediate alterations in both lower extremity kinematics and vGRFs. Running barefoot or in minimal shoes dramatically increased the AVLR, which has been associated with injury, compared with a traditional shoe. This study evaluated the effects of footwear on overground running biomechanics, including AVLR, in pre- and early-adolescent youth males. Based on our findings, clinicians should exercise caution in barefoot or minimal shoe transition among young, habitually shod, runners due to the immediate and dramatic increases in AVLRs.

Recreational Runners Gain Physiological and Biomechanical Benefits From Super Shoes at Marathon Paces.

Advanced footwear technology is prevalent in distance running, with research focusing on these "super shoes" in competitive athletes, with less understanding of their value for slower runners. The aim of this study was to compare physiological and biomechanical variables between a model of super shoes (Saucony Endorphin Speed 2) and regular running shoes (Saucony Cohesion 13) in recreational athletes. We measured peak oxygen uptake (VO2peak) in 10 runners before testing each subject 4 times in a randomly ordered crossover design (ie,Endorphin shoe or Cohesion shoe, running at 65% or 80% of velocity at VO2peak [vVO2peak]). We recorded video data using a high-speed camera (300Hz) to calculate vertical and leg stiffnesses. 65% vVO2peak was equivalent to a speed of 9.4km·h-1 (0.4), whereas 80% vVO2peak was equivalent to 11.5km·h-1 (0.5). Two-way mixed-design analysis of variance showed that oxygen consumption in the Endorphin shoe was 3.9% lower than in the Cohesion shoe at 65% vVO2peak, with an interaction between shoes and speed (P = .020) meaning an increased difference of 5.0% at 80% vVO2peak. There were small increases in vertical and leg stiffnesses in the Endorphin shoes (P < .001); the Endorphin shoe condition also showed trivial to moderate differences in step length, step rate, contact time, and flight time (P < .001). There was a physiological benefit to running in the super shoes even at the slower speed. There were also spatiotemporal and global stiffness improvements indicating that recreational runners benefit from wearing super shoes.

Walking with individualized 3D-printed minimal footwear increases foot strength and produces subtle changes in unroll pattern

IntroductionThis 5-month follow-up study, involving 66 subjects (38 intervention, 28 control; 34 females, 32 males), evaluated the biomechanics of walking while wearing bespoke, 3D-printed footwear.MethodsA 3D scanner was used to obtain foot shape, which was subsequently modified to yield a suitable instep and additional room in the forefoot and toe areas, to allow for potential shape changes of the foot. Shoes were manufactured using TPU laser sintering. Pre (T0) and post (T1) the intervention, plantar pressures were collected using a plantar pressure plate (3 trials per foot) and toe flexor strength (5 trials per foot) was measured using a dynamometer, for control and intervention groups. Plantar pressure peak patterns and center-of-pressure (CoP) timing was analysed using 2D and 1D Statistical Parametric Mapping, respectively. Toe strength changes were expressed in percent and per individual as: 100 x ((strength@T1strength@T0) / strength@T0).ResultsPeak pressure distribution did not differ between control and intervention populations, or between T0 and T1. Center-of-pressure unroll differed between barefoot and shod conditions at T0 for the intervention group. When barefoot, the intervention group at T1 showed a more lateral CoP in early stance and a more anterior CoP in late stance compared to T0. In the intervention group, toe strength increased significantly by 48.5% between T0 and T1.DiscussionOverall, the results indicate that the bespoke, 3D-printed footwear did not significantly affect peak pressure distribution compared to barefoot walking. However, center-of-pressure patterns during gait were influenced, particularly in the intervention group, with analysis indicative of barefoot subjects' CoP moving faster in early and mid-stance than when shod. Additionally, the intervention led to a significant increase in toe strength. These findings contribute to our understanding of the biomechanical effects of customized 3D-printed footwear and highlight the potential benefits of such interventions in improving foot function and strength.

Kinematic variations in the barbell back squat under different footwear conditions in female college athletes.

The barbell back squat is one of the most performed exercises, being important for the strengthening of lower limbs and trunk. Recently, it has become popular to train under different conditions of footwear or without it, and some investigations have analyzed the changes that this brings, with some contradictions in this regard. The purpose of this study was to analyze the kinematic variations under different shoe conditions (running shoes, barefoot and barefoot with heel raised) in the back squat in female university athletes. Fifteen athletes in the three conditions with a load equal to 70% of their one-maximum repetition (1RM), were recorded and analyzed to determine the angles of the ankle, knee, hip and trunk by five movements in each condition. The use of enhancement significantly increased (P<0.05) the dorsal flexion angle of the ankle, against the footwear condition and barefoot without enhancement (109.6±11.1° vs. 99.1±9.0° vs. 101.3±11.5°). No significant differences were observed in any of the other variables. An optimal squat technique is important for preventing injuries, optimal rehabilitation and for improving sports performance. Increased dorsal ankle flexion angle may protect distal tibiofibular joint.

Evaluation of hoof morphometry in normal and lame polo horses at Ibadan Polo Club.

This study evaluated the changes in hoof morphometric parameters between normal and lame polo horses. Cross-sectional survey of hoof morphometric parameters of polo horses was conducted at the Ibadan Polo club. Also, each horse was physically examined and severity of lameness scored based on the criteria by American Association of Equine Practitioners. Differences in morphometric parameters between sex, lameness status and shoeing status were analyzed using Student’s t test and values were considered significant at p&lt; 0.05) higher in females (118.8 ± 9.3mm; 117.1 ± 8.3mm) than male horses (109.8 ± 6.1 mm; 106.8 ± 12.1 mm). Hoof wall angles did not differ significantly (p &gt; 0.05) between the sexes. Majority of the hoof morphometric parameters were significantly (p&lt; 0.05) higher in shod horses compared to unshod horses. In addition, the dorsal hoof wall angle of the right hind limb was significantly (p &lt; 0.05) higher in lame (61.3 ± 11.50) than normal horses (53.6 ± 8.30). It was concluded that shoeing conditions and lameness significantly alters hoof morphometric parameters of polo horses.

Effects of Biomimetic Shoes on Healthy Young Children's Gait.

Objective To compare the spatial-temporal parameters and walking kinematics of toddlers wearing biomimetic shoes, regular shoes (daily use owned shoes), and barefoot. Methods Spatial-temporal parameters (speed, step length, and stride width), the mean vertical displacement of the center of mass (COM), knee flexion peak, and maximal foot height were analyzed. Results Children were not different in biomimetic shoes and barefoot conditions on speed, step length, and COM vertical displacement. There was no difference among conditions on stride width and foot height. The knee flexion peak was greater in shod conditions than barefoot. The regular shoes showed greater COM vertical displacement than biomimetic shoes and barefoot. Conclusion The findings showed that shoes affected the walking pattern in young children, but a shoe with a biomimetic design had a lesser effect on the walking pattern.

Effects of Barefoot and Shod Conditions on the Kinematics and Kinetics of the Lower Extremities in Alternating Jump Rope Skipping-A One-Dimensional Statistical Parameter Mapping Study.

To explore the difference in the biomechanics of the lower extremity during alternating jump rope skipping (AJRS) under barefoot and shod conditions. Fourteen experienced AJRS participants were randomly assigned to wear jump rope shoes or be barefoot (BF) during the AJRS at a self-selected speed. The Qualisys motion capture system and Kistler force platform were used to synchronously collect the ground reaction forces and trajectory data of the hip, knee, ankle, and metatarsophalangeal (MTP) joints. One-dimensional statistical parameter mapping was used to analyze the kinematics and kinetics of the lower extremity under both conditions using paired t-tests. Wearing shoes resulted in a significant decrease in the ROM (p < 0.001) and peak angular velocity (p < 0.001) of the MTP joint during the landing phase. In addition, the MTP joint power (p < 0.001) was significantly larger under shod condition at 92-100% of the landing phase. Moreover, wearing shoes reduced the peak loading rate (p = 0.002). The findings suggest that wearing shoes during AJRS could provide better propulsion during push-off by increasing the MTP plantarflexion joint power. In addition, our results emphasize the significance of the ankle and MTP joint by controlling the ankle and MTP joint angle.

The use of preferred footwear versus barefoot conditions in gait analysis: A methodological investigation

Laboratory-based gait analyses traditionally analyze baseline characteristics in individuals while they are barefoot. However, there is limited evidence on whether individuals’ preferred walking shoes alter lower extremity kinematics during over-ground walking. We present novel evidence regarding the effects of shoes on lower extremity kinematics in healthy, young adults. Fifteen volunteers participated in this study which obtained lower extremity kinematic data on two over-ground walking conditions (barefoot and preferred shoes). Gait velocity, stance width, and stride length, along with sagittal plane hip, knee, and ankle angular positions were computed; hip, knee, and ankle positions were normalized to 100% of the stride. Dependent t-tests were used to compare baseline and shoe conditions for gait velocity and stance width; a two-way analysis of variance was used for stride length. A point-by-point Model Statistic analysis was used to identify significant differences in angular joint positions between conditions. Our results indicate that shoes affected the ankle angular joint position for more than half of the gait cycle, and affected the knee angular joint position, but only for approximately 20% of the cycle. The hip was unaffected by shoes. Gait velocity and stance width were statistically significant, with gait velocity being greater for shoes, and stance width being greater while barefoot. Stride length was not statistically significant between conditions. These outcomes suggest that researchers should use caution if they are considering a barefoot condition as a ‘baseline’ for healthy, young adults, as there are marked changes in the ankle, and in traditional gait metrics.

Differences between barefoot and shod performance in selected fitness tests in adolescents

Physical fitness is an important health indicator and component of physical literacy. Therefore, monitoring youth fitness performance is crucial for identifying potential health risks and tracking physical literacy development. Over the years, many fitness test batteries have been developed while different protocols for footwear have been used in fitness testing. The comparison of fitness results performed in different footwear could therefore be questioned. Thus, the purpose of this study was to examine the differences between barefoot and shod performance of selected motor tests in adolescents. Eighty-six adolescents aged between 14 and 16 years performed standing long jump, 20-m shuttle run, and polygon backwards in both footwear conditions. A strong correlation (r=0.83-0.95) was noted between both performances. No significant differences between barefoot and shod performance in the standing long jump and the backward obstacle course test were found, while significant differences were noted in the 20-m shuttle run. In this test, both, boys and girls performed better in shod conditions. Interestingly, there were no significant differences in performance of all tests among those who are habitually barefoot and others. From practical perspective, this study demonstrated that researchers could compare scores of samples in barefoot and shod performance of standing long jump and backward obstacle course tests. However, when physical teachers compare individual scores over the years, this should be made under the same footwear conditions, as differences in test conditions can provide a distorted picture of motor development.

Well-trained Endurance Runners' Foot Contact Patterns: Barefoot vs. Shod Condition.

We aimed to investigate the initial foot contact and contact time in experienced endurance runners at individualized speeds, in running shoes and barefoot. Forty-eight participants (33.71±7.49 y, 70.94±8.65 kg, 175.07±7.03 cm, maximum aerobic speed 18.41±1.54 km.h-1) were distributed into three groups according to athletic performance: highly-trained runners, middle-trained runners, and control group. An incremental running test until exhaustion was performed for assessing maximum aerobic speed. After≥24 h of recovery participants randomly walked and ran, barefoot and in running shoes, over a pressure plate at ~4.7 km.h-1 and 85% of the maximum aerobic speed, respectively. They wore the same model of running shoes with homogeneous lacing pattern. A rearfoot strike was performed by 68.8% and 77.1% of participants when running barefoot and in running shoes, respectively. Considering the tendency to develop a rearfoot strike was lower in the barefoot condition, runners with higher performance may benefit from training in minimalist running shoes because their foot contact pattern could tend towards a non-rearfoot strike. Our results suggest that initial foot contact and contact time are related to running performance and may also be influenced by running shoes.

Larger Achilles and plantar fascia induce lower duty factor during barefoot running

ObjectivesTendons play a crucial role allowing the storage and release of mechanical energy during the running cycle. Running kinematics, including duty factor, constitute a basic element of the runner's biomechanics, and can determine their performance. This study aimed to analyze the link between Achilles tendon and plantar fascia morphology and running parameters, considering the influence of wearing shoes versus running barefoot. DesignCross-sectional study. Methods44 participants (30 men and 14 women) engaged in two running sessions, one with shoes and one without, both lasting 3 min at a consistent speed of 12 km/h. We captured running kinematic data using a photoelectric cell system throughout the sessions. Before the trials, we measured the thickness and cross-sectional area of both the Achilles tendon and plantar fascia using ultrasound. ResultsThe Pearson test revealed a significant correlation (p < 0,05) between Achilles tendon and plantar fascia morphology and contact time (r > −0.325), flight time (r > −0.325) and duty factor (ratio of ground contact to stride time) (r > −0.328) during barefoot running. During the shod condition, no significant correlation was found between connective tissue morphology and kinematic variables. ConclusionsIn barefoot running, greater size of the Achilles tendon and plantar fascia results in a reduced duty factor, attributed to longer flight times and shorter contact times.

Effects of different habitual foot strike patterns on in vivo kinematics of the first metatarsophalangeal joint during shod running-a statistical parametric mapping study.

Existing studies on the biomechanical characteristics of the first metatarsophalangeal joint (1st MTPJ) during shod running are limited to sagittal plane assessment and rely on skin marker motion capture, which can be affected by shoes wrapping around the 1st MTPJ and may lead to inaccurate results. This study aims to investigate the in vivo effects of different habitual foot strike patterns (FSP) on the six degrees of freedom (6DOF) values of the 1st MTPJ under shod condition by utilizing a dual-fluoroscopic imaging system (DFIS). Long-distance male runners with habitual forefoot strike (FFS group, n = 15) and rearfoot strike (RFS group, n = 15) patterns were recruited. All participants underwent foot computed tomography (CT) scan to generate 3D models of their foot. The 6DOF kinematics of the 1st MTPJ were collected using a DFIS at 100Hz when participants performed their habitual FSP under shod conditions. Independent t-tests and one-dimensional statistical parametric mapping (1-d SPM) were employed to analyze the differences between the FFS and RFS groups' 1st MTPJ 6DOF kinematic values during the stance phase. FFS exhibited greater superior translation (3.5-4.9mm, p = 0.07) during 51%-82% of the stance and higher extension angle (8.4°-10.1°, p = 0.031) during 65%-75% of the stance in the 1st MTPJ than RFS. Meanwhile, FFS exhibited greater maximum superior translation (+3.2mm, p = 0.022), maximum valgus angle (+6.1°, p = 0.048) and varus-valgus range of motion (ROM) (+6.5°, p = 0.005) in the 1st MTPJ during stance. The greater extension angle of the 1st MTPJ in the late stance suggested that running with FFS may enhance the propulsive effect. However, the higher maximum valgus angle and the ROM of varus-valgus in FFS may potentially lead to the development of hallux valgus.

Gait variability of interlimb coordination in high-heeled shoes with detachable base sockets under conditions of sinusoidal speed change

BackgroundThis study aimed to investigate the effects of wearing high-heeled shoes (HHS) on gait variability of the lower limbs when the treadmill speed was sinusoidally changed. MethodsA total of 17 young females walked on a treadmill with HHS, HHS with detachable base sockets (HHS-Sockets), and low-heeled shoes (LHS) under sinusoidal speed-changing protocol of 60-s and 30-s periods with an amplitude of ± 0.56 m·s-1. The time course of the joint elevation angles of the thigh, shank, and foot in one gait cycle can be well approximated like a plane in a triaxial space, so-called intersegmental coordination (IC). Standard deviation of the plane (IC thickness) was considered as the anteroposterior gait variability when the best-fitting plane of the angular covariation was obtained. The lateral gait variability was the coefficient of variance of step width (CVSW). To examine whether the gait parameters was associated with IC thickness, a sum of the time delay of the stride length and step frequency (TDSL+SF) against sinusoidal speed change was calculated. ResultsThe IC thickness was not different across shoe conditions and periods. The CVSW was greater in the HHS and HHS-Sockets conditions than in the LHS condition. TDSL+SF was greater in the HHS condition than in the LHS and HHS-Sockets conditions at both periods; however, it was not correlated with IC thickness. SignificanceWalking with HHS increased lateral gait variability at faster speed-changing situation, but not anteroposterior gait variability. Detachable sockets expanding the base area ten times greater than that of HHS could reduce TDSL+SF; however, TDSL+SF could not explain the IC thickness.

The clinical and biomechanical effects of customized foot orthoses in individuals with plantar heel pain: A pre-post intervention study

BackgroundCustomized foot orthoses (CFOs) are often recommended for the management of plantar heel pain. However, there is a lack of information regarding lower limb and multi-segment foot motion during gait. Research questionThis study aimed to determine the effects of heat moulded CFOs on foot and lower limb kinematics when compared with prefabricated foot orthoses (PFOs) and wearing no orthoses (shod condition), and to determine the short-term effects of CFOs on pain intensity and foot function. MethodsThe immediate effects of CFOs on the lower limb and multi-segment foot motion were assessed. Participants were then asked to use the CFOs for one month and foot pain, function, and temporal-spatial parameters were assessed at baseline and at one month follow up. ResultsThirty-five participants (22 females), aged 40.1 (10.5) years, with a mean duration of symptoms of 12.59 months were recruited. The symptomatic limbs showed a higher forefoot varus angle and greater rearfoot and forefoot corrections were required compared to the non-symptomatic limbs. When compared with PFOs and shod conditions, CFOs provided the least forefoot and knee motion in the transverse plane during contact phase (P < 0.05, d=0.844–1.720), least rearfoot motion in the coronal plane during midstance (P < 0.05, d=0.652), and least forefoot motion in the frontal plane, knee motion in the transverse plane, and hallux motion during the propulsive phase (P < 0.05, d=0.921–1.513). Significant improvements were seen for foot pain and function (P < 0.05, d=1.390–2.231) with significant increases in cadence and walking velocity after one month of CFO use (P < 0.05, d=0.315–0.353), and those most likely to respond had greater pain and less ankle eversion (P < 0.05, d=0.855–1.115). SignificanceCFOs appear to improve pathological biomechanics associated with plantar heel pain. After one month follow up, the CFOs decreased pain intensity and increased foot function, and showed significant improvements in temporal and spatial parameters of gait.

Foot Sole Contact Forces vs. Ground Contact Forces to Obtain Foot Joint Moments for In-Shoe Gait-A Preliminary Study.

In-shoe models are required to extend the clinical application of current multisegment kinetic models of the bare foot to study the effect of foot orthoses. Work to date has only addressed marker placement for reliable kinematic analyses. The purpose of this study is to address the difficulties of recording contact forces with available sensors. Ten participants walked 5 times wearing two different types of footwear by stepping on a pressure platform (ground contact forces) while wearing in-shoe pressure sensors (foot sole contact forces). Pressure data were segmented by considering contact cells' anteroposterior location, and were used to compute 3D moments at foot joints. The mean values and 95% confidence intervals were plotted for each device per shoe condition. The peak values and times of forces and moments were computed per participant and trial under each condition, and were compared using mixed-effect tests. Test-retest reliability was analyzed by means of intraclass correlation coefficients. The curve profiles from both devices were similar, with higher joint moments for the instrumented insoles at the metatarsophalangeal joint (~26%), which were lower at the ankle (~8%) and midtarsal (~15%) joints, although the differences were nonsignificant. Not considering frictional forces resulted in ~20% lower peaks at the ankle moments compared to previous studies, which employed force plates. The device affected both shoe conditions in the same way, which suggests the interchangeability of measuring joint moments with one or the other device. This hypothesis was reinforced by the intraclass correlation coefficients, which were higher for the peak values, although only moderate-to-good. In short, both considered alternatives have drawbacks. Only the instrumented in-soles provided direct information about foot contact forces, but it was incomplete (evidenced by the difference in ankle moments between devices). However, recording ground reaction forces offers the advantage of enabling the consideration of contact friction forces (using force plates in series, or combining a pressure platform and a force plate to estimate friction forces and torque), which are less invasive than instrumented insoles (which may affect subjects' gait).

Increased Barefoot Stride Variability Might Be Predictor Rather than Risk Factor for Overuse Injury in the Military.

Footwear usage could be a promising focus in reducing musculoskeletal injury risk in lower extremities commonly observed among the military. The goal of this research was to find potential gait-related risk factors for lower leg overuse injuries. Cases (n = 32) were active-duty infantry soldiers who had suffered an overuse injury in the previous six months of service before enrolling in the study. The control group (n = 32) included infantry soldiers of the same age and gender who did not have a history of lower leg overuse injury. In the gait laboratory, individuals were asked to walk on a 5-m walkway. Rearfoot eversion, ankle plantar/dorsiflexion and stride parameters were evaluated for barefoot and shod conditions. Barefoot walking was associated with higher stride time variability among cases. According to the conditional regression analysis, stride time variability greater than 1.95% (AUC = 0.77, 95% CI (0.648 to 0.883), p < 0.001) during barefoot gait could predict lower leg overuse injury. Increased barefoot gait variability should be considered as a possible predictive factor for lower leg overuse injury in the military, and gait with military boots masked stride-related differences between soldiers with and without lower leg overuse injury.

The Effect of Non-Newtonian Fluid Midsole Footwear on Lower Limb Biomechanics after 5 km of Running in High Temperature

This study’s aim was to examine the effect of non-Newtonian fluid (NN) shoe and ethylene vinyl acetate (EVA) shoe on human lower limb biomechanics and muscle activation during running in hot temperatures. Thirty-five men utilizing a rearfoot strike ran 5 km at a self-selected tempo at an average summer temperature of 41.7 ± 1.0 °C and relative humidity of 80.7 ± 3.5%. The kinematics, kinetics, and muscle activation of the right leg were monitored from landing until the pedal was off the ground. A two-way repeated-measures ANOVA was conducted to investigate the main effects of the shoe condition, temperature, and interaction effect. Wearing NN at high temperature resulted in increased hip range of motion (ROM) (p = 0.001). The knee torque increased significantly when wearing EVA and NN shoes after the temperature increased (p = 0.006). When wearing EVA and NN, the ground reaction force (GRF) and loading rate (LR) increased significantly after the temperature increased (p = 0.001; p = 0.009). When wearing NN after running for 5 km at a high temperature, the displacement range of center of pressure (COP) was significantly reduced (p &lt; 0.001), while the EVA was significantly increased (p &lt; 0.001). Neither pair of shoes substantially altered muscle activity. After excluding the factor of fatigue, the increase in temperature not only changed the properties of the material inside the shoe, but also changed the parameters of the biomechanics of the human lower limbs. After the temperature increases, the shoes made of non-Newtonian fluid materials can quickly stabilize under the condition of increased shear stress and reduce the displacement of the human body. Thus, it indicated that non-Newtonian fluid shoes may lower the risk of injury when running in extremely hot conditions.

Impact of bilateral motion control shoes with outsole adjustment on gait asymmetry in individuals with mild leg length discrepancy

BackgroundFootwear adjustment is recommended in the management plan of leg length discrepancy. However, it is not clear how the outsole of motion control shoe adjustment influences trunk symmetry and walking performance. Research questionDoes bilateral adjustment of the outsole affect trunk and pelvis symmetry and ground reaction force during walking in individuals with leg length discrepancy? Methods20 mild leg length discrepancy participants were recruited into a cross-sectional study. All subjects performed a walking trial with their habitual shoes to determine the outsole adjustment. Four trials of walking were carried out in the order of unadjusted and bilateral adjusted motion control air-cushion shoes. Shoulder level differences and trunk and pelvic motion were assessed, while the ground reaction force at the heel strike was reported. A paired t-test was performed to compare the differences between the conditions with a significance level at p < 0.05. ResultsDuring walking trials, mild leg length discrepancy participants with the adjusted shoe displayed lower variations in the maximum shoulder height differences (p = 0.001) and trunk rotation angle (p = 0.002) than those with the unadjusted shoe. Also, there was a significant reduction in the vertical ground reaction force (p = 0.030), but not in the anteroposterior or mediolateral directions, during walking in the adjusted shoe condition compared to the unadjusted shoe condition. SignificanceThe outsole adjustment of the bilateral motion control shoes can improve trunk symmetry while decreasing the ground impact at the heel strike. The study provides additional information to prescribe or recommend footwear adjustment to improve walking symmetry in leg length discrepancy participants.

Time course of muscle activation, energetics and mechanics of running in minimalist and traditional cushioned shoes during level running

The study aimed to compare the ankle muscles activation, biomechanics and energetics of running in male runners during submaximal level run using minimalist (MinRS) and traditional cushioned (TrdRS) running shoes. During 45-min running in MinRS and TrdRS, the ankle muscles pre- and co-activation, biomechanics, and energetics of running of 16 male endurance runners (25.5 ± 3.5 yr) were assessed using surface electromyography (tibialis anterior and gastrocnemius lateralis), instrumented treadmill and indirect calorimetry, respectively. The net energy cost of running (Cr) was similar for both conditions (P = 0.25) with a significant increase over time (P < 0.0001). Step frequency (P < 0.001), and total mechanical work (P = 0.001) were significantly higher in MinRS than in TrdRS with no evolution over time (P = 0.28 and P = 0.85, respectively). The ankle muscles pre- and co-activation during the contact phase did not differ between the two shoe conditions (P ≥ 0.33) or over time (P ≥ 0.15). In conclusion, during 45-min running, Cr and muscle pre- and co-activation were not significantly different between MinRS and TrdRS with significantly higher step frequency and total mechanical work noted in the former than in the latter. Moreover, Cr significantly increased during the 45-min trial in both shoe conditions along with no significant change over time in muscle activation and biomechanical variables.